> Consider - why is it important what gender someone is? Or age?
It really isn't when it comes to arguments. An argument should not be attached to whoever brought it up. If it is it's hardly an argument and most likely something personal or morally loaded which is not suited for objective discussion.
> Should emoji only have had unisex and age-less figures instead of its current set?
Yes!
> Is it sexist to use a female-presenting emoji?
Obviously not and I don't know why you would get the impression it is. It is however mostly irrelevant: So now people assume you are an XX chromosome female or are trying to present as one. What now? Do you expect special treatment now?
> These things all have obvious utility for communication,
No they don't? And I don't know what would be "obvious" about it? You can't just present this as "obvious" fact when it's really not clear at all.
> and you're ending up making some deeply strange arguments to try and dismiss that utility.
You did not explain to me why my arguments are "deeply strange" and you also failed to explain why it should be useful to convey your own skintone in the context of discussion. My argument is that all you do with skintones and a nursing male is to bring political discrimination into electronic discussion, without providing any benefit whatsoever or even doing harm.